Fluid lubricated bearing and pressure sensing control valve

ABSTRACT

A fluid lubricated bearing having a set of fluid receiving bearing cavities, each being in communication with a control valve which senses incipient positive or negative pressure change due to incipient movement of the shaft toward or away from the cavity, then amplifies the sensed change and feeds lubricating fluid to the corresponding bearing cavity at the pressure and rate needed to create a restoring force sufficient to minimize or prevent shaft displacement. The valve also being adapted to the control of fluid motors to detect incipient change in load, then responding by supplying more or less motor fluid as required.

United States Patent 1191 Whitaker July 31, 1973 FLUID LUBRICATEDBEARING AND Primary ExaminerMilton Kaufman PRESSURE SENSING CONTROLVALVE Assistant ExaminerFrank Susko [76] Inventor: William D. Whitaker,1512 E. 5th,

N0. 30, Ontario, Calif. 91762 i [57] ABSTRACT [22] Filed: Nov. 20,1970

Appl. No.: 91,278

Related US. Application Data A fluid lubricated bearing having a set offluid receiving bearing cavities, each being in communication with acontrol valve which senses incipient positive or negative pressurechange due to incipient movement of the shaft toward or away from thecavity, then amplifies the sensed change and feeds lubricating fluid tothe corresponding bearing cavity at the pressure and rate needed 52 us.Cl. 308/9 to create a restoring force sufficient to minimize or p 511Int. Cl. F16c 17/16 Shaft displacement The valve also bein adapted [58]Field of Search 308/9, 122 to the control of fluid motors to detectincipient change in load, then responding by supplying more or less [56]References Cited motor fluid as required.

UNITED STATES PATENTS 12 Claims, 32 Drawing Figures 3,1 l3,808 3/1961Carnol 308/722 Z0 7 Z5 0 Z3 FLUID LUBRICATED BEARING AND PRESSURESENSING CONTROL VALVE This application is a continuation-in-part of apreviously filed application, Ser. No. 754,1 l2, filed Aug. 15, I968 nowabandoned, which, in turn, is a continuation of application Ser. No.558,748, filed June 20, 1966, now abandoned.

BACKGROUND OF THE INVENTION Fluid lubricated bearings utilize fluidranging from a high density viscous fluid to'gaseous fluids. The bearingmay be conical, cylindrical, flat, spherical or other desired shape, andintended for radial or thrust loads or a combination of the two.Friction losses increase with velocity; hence, as the required shaftspeed increases, the viscosity of the lubricating fluid must be reducedto avoid excessive heating, or means be provided to circulate and coolthe lubricating fluid.

It is essential that a film of lubricant be maintained between thebearing and its shaft; otherwise, the bearing will fail. The problem ofmaintaining a film in-' creases with decreased viscosity. The problem offilm continuity is compounded by the fact that the shaft seldom runscompletely true; that is, the shaft may precess or whirl about thecenter of ,gravity of the rotating mass, the gravitational load imposedon the shaft may cause the shaft to displace from the center of thebearing. These displacement forces are resisted by the lubricant film.As the viscosity decreases, the resistance of the lubricant fllm to thedisplacement forces decreases, but is compensated in part by increasedlubricant pressure. If the lubricant is gaseous or compressible, aspring effect is added, which may also pro duce vibration, the frequencyof which is influenced by several factors.

Various partial solutions to the problems indicated have been found,principally by use of more viscous fluids, circulation of the fluids athigh pressure, and external cooling of the fluids. In many cases, itwould be preferred to use fluids of low viscosity including gaseousfluids such as air, but the load and velocity requirements oftenprohibit use of such lubricants.

Should it be possible to sense at different locations within the area ofthe bearing, the need of additional lubricant and then supply theadditional lubricant, or the need of less lubricant and then reduce thesupply, the viscosity of the fluid could be reduced to the point thatair may be used in many cases where a viscous liquid lubricrant is nowrequired.

Also, in the operation of various fluid motors, especially, but notlimited to air driven motors, it would be desirable that means beprovided which would sense the load demand and compensate by providingadditional or less motive fluid as required.

BACKGROUND OF THE INVENTION AS IT PERTAINS TO FLUID BEARINGS FHP:5,280,000 T with FHP Friction Horsepower V= Viscosity, In Centipoise LBearing Length, In inches D Bearing Diameter, In Inches N Speed, in RPMT= Film Thickness, In Inches At atmospheric pressure and F., the ratioof air viscosity to water viscosity is:

V (AIR)/V (WATER) 0.020/0.43 l/2l.5

and the ratio of air viscosity to S.A.E. 10 oil viscosity is:

V (AIR)/V (S.A.E. l0 OIL) 0.020/l0 H500 the shaft as follows:

r s +FDL with F Bearings Total Load Capacity, In Lbs.

F Dynamic Lift Forces Including The Dashpot Damping Force, In Lbs.

F S Supply Pressure Lift Force, In Lbs.

The bearings total load is the resultant force of the forces acting onthe bearing as follows:

with

L Total Load, In Lbs.

S Shaft Weight, In Lbs.

S Shaft Centrifugal Load, In Lbs.

S Shaft Gyrosopic Load, In Lbs.

S Load Applied To The Shaft, In Lbs.

The natural frequency of vibration of the shaft weight supported on thebearings fluid film is:

with

f= The Natural Frequency, In CPS K The Film Spring Rate, In Lbs/Inch ofDeflection K F/D Force/Deflection G The Gravitational Constant, InInches/SEC? W Shaft Weight, In Lbs.

If the fluid springs are compressed with a force acting on the shaft andreleased the shaft tends to vibrate at its natural frequency ofvibration until the stored up energy is absorbed in damping as follows:ENERGY E FD/2 M w/G) V. V

FD 2 G A I W V= VELOCITY,

The spring rate or stiffness is increased by reducing the fluid filmspring deflection with respect to the rotor weight as follows:

The centrifugal force created by the rotation of the center of gravityaround the shaft center or around the center of the bearing is equal tothe lift force of the supporting fluid film spring at the naturalfrequency of vibration of the shaft on the fluid springs as follows:

F=W/G (21rf) D=KD Therefore, the orbit of the center of gravity of theshaft around the center of rotation tends to increase at a rotationalfrequency equal to the natural frequency of vibration of the shaft onits supporting fluid flim.

D The Radius Of The Orbit Of The Shafts Center Of Gravity Around TheCenter Of Rotation Of A Balanced Shaft.

In an actual rotor the CC. is displaced a distance x from the center ofthe shaft and the center of the shaft is displaced a distance y from thecenter of rotation, then the centrifugal force is:

F: W16 2 W13 (y+ x) That is below the natural frequency of vibration andthe spring force is:

F KD, since K F/D Equating forces:

KD W/G (2 1rf) (y+ Then above the natural frequency of vibration due toshaft rotation around the center of gravity:

The orbit of the shafts center of gravity also increases at rotationalfrequencies 2,3,4,6, etc. times the natural frequency of vibration.These are called harmonic frequencies in physics.

An objective of the pressure sensing fluid flow control is to amplify asmall change in the fluid lubricating film pressure to increase thestiffness of the low viscosity fluid film. Referring to FIG. 12, thefluid lubricating bearing film pressure vs. time diagram which shows asmall change in film pressure being amplified according to the followingamplification ratio equation, A for a gas fluid and A,, for a liquidfluid.

Gain in pressure Small change in pressure The flow of a gas through athin plate orifice per Reynolds (Trans. ASME, I916, P. 799) was found tobe:

W, 0.425 D (P, 2 P T,-

with

W, Flow, Lb. Per Sec.

D Orifice Dia., Inches P, Inlet Pressure, PSIA.

R Discharge Pressure, PSIA.

T, Inlet Temperature, Deg. R. for

P /P,= l to 0.13

The flow of a liquid through a sharpedge orifice is found to be:

with

Q Flow, CFS. D Orif. Dia., FT. H Head, FT.

G Gravity AcceL, F/S/S.

The flow of a liquid through a capillary tube per Poiseville in I842 wasfound to be:

H/L 28.3 (M/S) (Q/D) with H Head Loss, FT.

L Length, FT. I

Q Flow, Cu. FT. SEC.

M Viscosity, Poises.

S Specific WT., Grams/CC.

D Dia., Inches.

The flow of a gas through a capillary tube is found by combining theabove gas flow EQ. for an ORIF. with the above liquid flow EQ. for acapillary tube into the following practical equation:

W, 0.424 (P, Pf) (SIM) (Di/l) with W, Flow,.Lbs/SEC.

L Length, Inches.

P, Inlet Pressure, PSIA.

P Discharge Pressure, PSIA.

M Viscosity, Poises.

S Specific Wt., Grams/CC.

NOTE: Use the Orif. Flow EQ. up to L 3D, due to the contraction of thejet aft of the tube inlet.

The flow of a liquid through a thin slot per Fuller was found with thefollowing equation: I

with

Q Flow, CU. INJSEC.

P, Inlet Pressure, PSI.

P, Discharge Pressure, PSI.

B Breadth, Inches T Thickness, Inches M Viscosity, Lb. SEC/IN L Length,Inches The flow of a gas through a thin slot is found by substitutingkinematic viscosity for M and (P, P for (P, 6 P in Fuller's equation forthe flow through'a thin slot as follows:

W A 839 (P, P B T" (SIM) I! with W, Flow, Lbs/SEC. P, Inlet Pressure,PSIA. P Discharge Pressure, PSIA.

B Breadth, lnches Thickness, Inches M Viscosity, Poises S Specific Wt.,Grams/CC.

Dashpot damping is proportional to velocity which is proportional tofrequency as shown in the following equation:

f= V/1r A with V Max. Velocity, lnches Per SEC.

f= Frequency, Cycles Per SEC. A Amplitude, Inches.

SUMMARY OF THE INVENTION The present invention is directed to a fluidlubricated bearing and pressure sensing control valve which issummarized in the following objects:

First, to provide a fluid lubricated bearing and novelly arrangedpressure sensing control valve wherein the bearing is provided with aset of lubricating pressure fluid receiving bearing cavities, each incommunication with a corresponding control valve which incorporates anovel means of sensing incipient positive or negative pressure change inits corresponding bearing cavity caused by incipient displacement of theshaft to or from the bearing cavity, then amplifying the sensed changeand increasing or decreasing the lubricant fluid supply to thecorresponding bearing cavity so as to apply a restoring force sufficientto prevent or minimize shaft displacement.

Second, to provide a control valve, as indicated in the precedingobject, which is capable of extremely rapid response to compensate fortransient shaft displacement forces as well as more permanently orconsistently applied forces.

Third, to provide a fluid lubricated bearing and control valve, asindicated in the preceding objects, which permits the use of lowviscosity lubricants under greater load conditions than has heretoforebeen considered possible; more particularly, while not limited togaseous lubricants, permits the use of air to attain high shaft speedswith increased loads while assuring that the proper lubricant film ismaintained even during starting and stopping conditions.

Fourth, to provide a pressure sensing control valve which is not limitedfor use in the control of bearing fluid pressures, but is adapted foruse wherever it is desired to sense incipient fluid pressure change andrespond by increasing or decreasing the fluid supply to augment thechange.

Fifth, to provide a pressure sensing control valve having an incipientpressure change sensing means, as indicated in the preceding object,which may be adapted for the control of a fluid motor; for example, afluid motor intended to drive a drill or other tool. In such case,incipient increased or decreased load on the motor due to change in loadon the tool causes the sensing means to respond by supplying anappropriately amplified increased or decreased quantity of motive fluidto compensate for the change in load.

Sixth, to provide a pressure sensing control valve, as indicated in thepreceding object, which incorporates a novel manually operated means foroverriding the sensing means whereby the valve may be caused to operateat full volume or a predetermined maximum volume irrespective of itssensing means.

Seventh, to provide a pressure sensing control valve which, with minorchanges in the porting, is adaptable to a wide range of applications.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary sectional view, withportions in elevation, of a conical fluid lubricated bearing having aset of pressure sensing control valves.

2 is a fragmentary transverse sectional view, taken through 2-2 of FIG.1.

FIG. 3 is an enlarged fragmentary sectional view, taken within Circle 3of FIG. 1, showing particularly one of the pressure sensing controlvalves.

FIG. 4 is a further enlarged fragmentary sectional view, taken withinCircle 4 of FIG. 3, showing particularly the sensing valve inlet port inits closed or minimum flow condition.

FIG. 5 is a fragmentary sectional view, corresponding to FIG. 4, butshowing the inlet port in its open condition.

FIG. 6 is a transverse sectional view, showing a cylindrical bearing anda set of pressure sensing control valves, portions taken in differentplanes, indicated by A, B, C, D, E and F.

FIG.7 is an enlarged fragmentary sectional view, taken through 77 ofFIG. 6, showing one of the pressure sensing control valves, andindicating by A, B, C, D, E and F the section planes of FIG. 6.

FIG. 8 is a further enlarged fragmentary sectional view, taken throughCircle 8 of FIG. 7, showing particularly the sensing valve inlet port inits closed or minimum flow condition.

FIG. 9 is a similar fragmentary sectional view, showing the inlet portin its open condition.

FIG. 10 is a sectional view of the pressure sensing control valvearmature, as illustrated in FIG. 7, to which has been added an inertiadevice.

FIG. 11 is a fragmentary diagrammatical sectional view, similar to FIG.7, illustrating the pressure conditions in the various passages andchambers of the pressure sensing control valve.

FIG. 12 is a diagram, indicating the relationship of the pressure sensedby the control valve and the gain in pressure as supplied to the hearingor other device associated with the control valve.

FIG. 13 is a diagram, illustrating the relationship of bearing fllmthickness to bearing film pressure.

FIG. 14 is an enlarged fragmentary diagrammatical sectional view of ashaft and the surrounding bearing, with the bearing film thicknessandthe eccentricity of the shaft greatly exaggerated for purposes ofillustration.

FIG. 15 is a diagram, indicating the relationship between valve outputpressure and the movement of the valve armature.

FIG. 16 is an elevational view of a pressure sensing control valve,adapted for the operation of fluid motors or the like.

FIG. 17 is an enlarged longitudinal sectional view, taken through l7--17of FIG. 16.

FIG. 18 is a longitudinal sectional view, taken through l8-l8 of FIG.17.

FIG. 19 is a sectional view of the bypass control block or plug shown inFIG. 17 and 18.

FIG. 20 is a transverse sectional view thereof, taken through 20-20 ofFIG. 19.

FIG. 27 is an enlarged longitudinal sectional view thereof, takenthrough 27-27 of FIG. 26.

FIG. 28 is a longitudinal sectional view thereof, taken through 28-28 ofFIG. 27.

FIG. 29 is an elevational view of a further modified form of thepressure sensing control valve.

FIG. 30 is an enlarged longitudinal sectional view thereof, takenthrough 30-30 of FIG. 29.

FIG. 31 is a longitudinal sectional view thereof, taken through 31-31 ofFIG. 30.

FIG. 32 is a fragmentary sectional view, similar to FIG. 7, illustratinga modified form of the pressure sensing control valve.

Reference is first directed to FIGS. 1 through 5. The construction hereillustrated is a fluid lubricated bearing and pressure sensing controlvalve which is intended primarily to utilize air as the lubricant, butmay, if desired, employ a low viscosity liquid. A shaft 1 is provided,having a conical journal 2 surrounded by a bearing body 3 which, inturn, is contained in a housing structure 4. The bearing body 3 isprovided with a conical bearing surface conforming to the journal 2.

Formed in the bearing surface is a set of bearing lubricant cavities 6,separated by webs 7. The cavities 6 occupy the major portion of thebearing surface. The cavities 6 terminate a short distance from thesmaller end of the bearing surface and are separated by a circular web 8from an annular vent cavity 9. The vent cavity, in turn, is separated byan annular web 10 from a set of pressure sensing cavities 11,corresponding in 1 number and position to the lubricant cavities 6.

Disposed in the bearing body 3, radially outward from each lubricantcavity 6 and its pressure sensing cavity 11, is an axially directedsensing valve bore 12. Each sensing valve bore is provided with a port13 communicating with a corresponding bearing fluid cavity, aconstricted port 14 communicating with the vent cavity 9 and a port 15communicating with the corresponding sensing cavity 11. The vent cavity9 is provided withone or more vent ports 16, exposed to the adjacentaxial end of the bearing body 3.

Each sensing valve bore 12 is provided near its inner end with ashoulder 17, beyond which is an inlet cavity 18, intersected by aradially extending inlet passage 19. The inlet passages 19 are suppliedfrom a common annular inelt manifold channel 20, surrounding the hearingbody 3 and flanked by seal rings 21. The housing structure 4 is providedwith a main supply port 22.

Fitted in each sensing valve bore 12 and seating against the shoulder 17is a fixed valve ring 23, having a bore 24 and an inlet port 25 slightlysmaller than the bore 24 and confronting the inlet passage 19. The valvering 23 is provided with an external annular channel 26 which registerswith the corresponding port 13 and is provided with one or more radialpassages 27.

The outer end of each sensing valve bore 12 receives a closure plug 28,fitted with a seal ring 29. The ring of closure plugs is held in placeby a common retainer ring 30, received in a mounting structure 31 intowhich one end of the housing structure 4 extends. The nature andconstruction of the mounting structure as well as the housing may varysubstantially depending upon the mechanism requiring the shaft 1 and itsbearing.

Each sensing valve bore 12 receives a reciprocal sensing valve piston32, having a valve head 33 of essentially the same diameter a the inletport 25. Adjacent the valve head 33, the piston 32 is provided with anannular channel 34, which communicates with the radial passages 27. Aswill be brought out in more detail hereinafter, the inlet port 25 andthe valve head 33 form cooperating valve lips 35 and 36, shown best inFIGS. 4 and 5, which, even in their closed" position do not form acomplete seal.

The outer end of the piston 32 is enlarged to fit a sensing valve bore,as indicated by 37. The outer extremity of the piston forms with theclosure plug 28 a pressure sensing chamber 38. The end of the closureplug facing into the pressure sensing chamber is pro vided with a recess39. The enlarged end 37 forms with the outer end of the valve ring 23 adamping chamber 40.

One or more restricted passages 41 extend between the pressure sensingchamber 38 and the damping chamber 40 through the enlarged end 37 of thepiston. Also, one or more restricted passages 42 extend between thepressure sensing chamber 38 and the channel 34. The external surface ofthe enlargedend 37 forms a bearing land 43, confronting the surface ofthe sensing valve bore 12. A second bearing land 44, formed between thechannel 34 and the enlarged end 37, confronts the bore 24 of the fixedvalve ring 23. Each sensing valve piston 32 is provided with an axiallyextending bore 45, exposed to the inlet cavity 18, and provided with aconstricted port 46 communicating with the pressure sensing chamber 38.Branching radially from the bore are bearing land passages 47 and 48,communicating with the bearing lands 43 and 44, respectively, to providelubrication for the sensing valve piston.

Operation of the embodimentof the fluid lubricated bearing and pressuresensing control valve illustrated in FIGS. 1 through 5 is as follows: i

The bearing and control valve are intended primarily for use of air orother gas as a lubricant. However, its

operation is not limited to a gaseous lubricant, but may utilize aliquid lubricant. in either case, the nature of the bearing and sensingvalves permits the use of lubricant having low viscosity, thuspermitting operations at higher speeds with minimal friction due to thelubricant itself so that the need of special cooling of the lubricant isminimized if not eliminated.

Prior to starting rotation of the shaft, lubricant under pressure issupplied through the port 22 and manifold channel 20 to all of thepressure sensing control valves.

As the valves do not completely close, fluid is admitted to each of thebearing lubricant cavities 6, through its corresponding pressure sensingvalve; that is, through channel 34, radial passages 27, channel 26 andthe ports 13. Lubricant fluid is also admitted to each of the pressuresensing cavities 11 through the axial bore 45,

constricted port 46, pressure sensing chamber 38 and ports 15. Eachpressure sensing control valve is, insofar as the main flow of fluid isconcerned, a balanced valve; that is, the pressure excited by the fluidas it flows from chamber 18 to passages 13 does not influence theposition of the valve.

Initially, before the lubricant reaches operating pressure, the journal2 rests on the lower side of the bearing surface. As the lubricantreaches its operating pressure, the lubricant vents from the upperbearing cavities 6 and pressure sensing cavities 11, with the resultthat a pressure drop occurs in the upper pressure sensing chambers 38,causing the upper valves to move towards a closed position withcorresponding pressure drop in the upper bearing cavities 6 and a netupward thrust of the lubricant in the lower bearing cavities to lift thejournal from the bearing surface so that the shaft is in condition forrotation.

When a rotational force is applied, the position of each valve adjustsin accordance with the pressure existing in its pressure sensing chamber38 and its corresponding pressure sensing cavity 11. It should be notedthat the axial travel of the valve piston is quite small and may be inthe order of only a few thousandths of an inch so that the adjustment ofthe valve piston to changes in pressure inits pressure sensing chamber38 may be extremely rapid. In order to control the rate of movement ofthe piston, the damping chamber 40 provides a back pressure on theenlarged end 37, counteracting the pressure in the sensing chamber 38.The size and number of the restricted passages 41 and 42, the size ofthe port 14 communicating with the vent cavity 9 are selected to obtainthe desired response of the valve piston and to prevent a hunting orfluttering condition. cavity It is intended that the pressure sensingvalve will have high gain. For example, when the journal 2 moves towarda pressure sensing cavity 11, causing a reduction in volume in thecavity, there is a slight rise in the pressure of the lubricant in thecavity 11 and its corresponding pressure sensing chamber 38. This causesthe valve piston to open further so as to admit pressure lubricant tothe corresponding bearing cavity 6. The volume of lubricant admitted issubstantially greater than the change in volume occurring in the cavity11 which causes the increased opening of the valve piston. When thepressure of the lubricant in the cavity 6 counterbalances the radialmovement of the journal, or perhaps causes a movement in the oppositedirection, a drop in pressure occurs in the cavity 11 resulting in adrop in pressure in the sensing chamber 38 and the movement of thepiston toward its closed position. However, as indicated previously, thesize and number ofthe restricted passages 41 and 42 and the constrictedport 46, in conjunction with the pressure feedback force acting on thefeedback pressure surface 49, prevents fluttering or hunting of thevalve piston.

Reference is now directed to FIGS. 6 through 9. The construction hereillustrated is directed particularly to a modified form of the pressuresensing control valve which may be adapted to the conical journal andbearing body of FIGS. 1 through 5, but is shown in connection with acylindrical journal and bearing body. More specifically, a shaft 51includes a cylindrical portion terminating at a shoulder 52, againstwhich is fitted a thrust bearing disk 53. The shaft is surrounded by acylindrical sleeve bearing 54, the outer periphery of which issurrounded by opposed beveled faces 55. The sleeve bearing is receivedin a housing 56, having a beveled internal portion 57 mating with one ofthe beveled faces 55. A beveled mounting ring 58 is attached to thehousing 56 and engages the other beveled face of the bearing 54 so as tosecure the sleeve bearing in position.

Between the beveled portions 55, the sleeve bearing 54 forms with thehousing 57 an annular inlet manifold 59, having a main inlet port 60.

The bearing 54 is provided with a set of axially extending sensing valvebores 61, corresponding to the sensing valve bores 12 of the firstdescribed structure. Each bore 61 is provided with an annular inletchannel 62, connected by a port 63 to the inlet manifold 59. The bore ofthe sleeve bearing 54 confronting the shaft 51 is provided with a set ofbearing or lubricant cavities 64, separated by webs 65 and terminatinginwardly from the axial ends of the sleeve bearing. A port 66 connectseach bearing cavity 64 to an annular outlet channel 67 formed in thecorresponding sensing valve bore 61 and axially offset from the inletchannel 62.

Each sensing valve bore 61 is closed at its ends by end plugs 68 and 69,which form with the sensing valve bore 61 a cylindrical chamber in whichis mounted a valve piston 70 in the form ofa hollow cylinder, closed atits ends by disks 71. Externally, each valve armature is provided withan annular connecting channel 72 positioned to bridge between thecorresponding inlet channel 62 and outlet channel 67. Correspondingportions of each inlet channel 62 and corresponding annular connectingchannel 72 form cooperative valve lips 73 and 74 which serve to regulatethe flow of lubricant fluid from the inlet channel 62 through theconnecting channel 72 and outlet channel 67 to the ports 66communicating with the bearing cavities 64.

At either side of the connecting channel 72, th valve piston 70 formsbearing lands 75 which confront the cylindrical walls of thecorresponding sensing valve bore 61. The valve piston forms acylindrical chamber 76, closed by the end disks 71. The radial walls ofthe valve piston are pierced with small inlet passages 77, communicatingbetween the corresponding inlet channel 62 and the chamber 76. Otherradial passages 78 and 79 communicate between the chamber 76 and thebearing lands 75 so that a lubricant film is maintained around thepiston 70 to reduce to a minimum the friction associated wijh movementof the piston.

The axially inner end of each piston 70 forms with the adjacent innerend plug 68 a sensing chamber 80. Similarly, the outer end of eachpiston forms with the corresponding outer end plug 69 a damping chamber81. The sensing chamber 80 corresponds in function to the sensingchamber 38 of the first described structure and the damping chamber 81corresponds to the damping chamber 40 thereof. One or more axiallyextending sensing chamber passages 82 connect the channel 72 with thesensing chamber 80, and a similar set of passages 83 connect the channel72 with the damping chamber 81. The effective area of the passages 83 isless than the area of the passages 82. One or more of the radialpassages 78 and 79 are intersected by axial passages 84, communicatingrespectively with the chambers 80 and 81. Each of the walls of the endplugs 68 and 69 or the end disks 84 confronting the chambers is providedwith an annular stop ridge 84a.

The inner end plug 68 is provided with an annular vent channel 85, whichcommunicates with the sensing chamber through a restricted passage 86. Avent outlet 87 registers with the channel 85 and extends through a wallof the sleeve bearing 54. The axially inner end of the end plug 68confronts the thrust bearing disk 53 and forms therewith a thrustbearing cavity 88. The thrust bearing cavity communicates with the inletmanifold channel 59 through a supply passage 89', extending partiallywithin the end plug 68 and partially within the sleeve bearing 54.

The outer end plug 69 is also provided with an annular vent channel 90,which communicates through a vent passage 91, formed partially in theend plug and partially in the sleeve bearing, with a correspondingbearing cavity 64. A needle valve 92 accessible from the outside of theend plug 69 controls the flow through the vent passage 91. A second ventpassage 93 communicates between the vent channel 90 and the exterior ofthe sleeve bearing 54 through a restricted vent outlet 94, which iscontrolled by a second needle valve 95, accessible from the exterior ofthe end plug 69.

Operation of the fluid lubricated bearing and pressure sensing controlvalve shown in FIGS. 6 through 9 is as follows:

As in the first described structure, the pressure fluid in its flow fromthe inlet 63 through channels 62, 67 and 72 to passage 66, exerts equalforce in opposite directions and does not effect a change in theposition of valve piston 70.

Also as in the first described structure, under initial static conditionwhen a pressurized lubricant is supplied, the shaft tends to centeritself as the lubricant tends to vent axially from the upper bearingcavities 64, causing a drop in pressure to be communicated from thesecavities through the passages 82 to the upper sensing chambers 80. Thisis accomplished more readily than the communication with the dampingchambers 81, with a result that the upper valve pistons move in adirection to close the spacing between the valve lips 73 and 74, whilethe lower valve piston moves in a direction to increase the spacingbetween the valve lips 73 and 74. The net result is that the shaft islifted or suspended free of the bearing ring prior to rotation. When theshaft is rotated, this condition is maintained; that is, a slightincrease in pressure caused by movement of the shaft radially in adirection to reduce the volume of a bearing cavity 64 is sensed byincreased pressure in the sensing chamber 80, which opens the spacingbetween the valve lips 73 and 74, causing lubricant fluid to be suppliedto the cavities 64' and exert an opposing force on the shaft and toreturn the shaft to its central position. I v

This condition is momentary for after a short delay determined by theeffective area of the damping chamber passages 83, the change ispressure is felt in the damping chamber 81, causing the pressures in thecavities 64 to adjust so that the shaft is properly suspended in thebearing. Lubricant is continuously fed into the sensing chamber throughthe corresponding perforation 84 and is vented therefrom through thevent passage 86. The two needle valves 92 and 95 control the flow fromthe passage 91 to the vent outlet 94 or the passage 96 to the dampingchamber 81 to alter the damping effect.

The end plugs 68 cooperate with the thrust bearing disk 53. In thestructure illustrated, a constant supply of lubricating fluid isdelivered to thrust bearing cavitites 88. However, where conditionswarrant, the pressure sensing valve structure employed to control theflow of air to the bearing cavities 64 may be employed.

Reference is now directed to FIG. 10; this construction utilizes thevalve piston as previously described except that a port 98 is located atthe center of each end disk 71 in addition to the ports 84. Also, thechamber 76 receives an inertia spool or mass compensator 99, havingrelatively thick end flanges connected by a stem 101. The peripheries ofthe flanges 100 form bearing lands 102 which are supplied with lubricantthrough T-passages 103, communicating with the chamber 76, and with theradial passages 77 and 79. The T-passages 103 also provide communicationbetween the end ports 98 and the chamber 76. The ends of the compensatorspool are provided with recesses 104.

The compensator spool operates as follows:

When the differential pressure acts on the ends of the valve piston, thecompensator spool tends to move first, followed almost instantly bymovement of the valve piston. Then the ratio of pressure forces actingon the compensator spool to the mass inertial force of the compensatorspool is smaller than the ratio of the pressure forces acting on thevalve piston to its mass inertia force. This causes the compensatorspool to move with respect to the valve piston and change thedifferential pressure to initiate conditions for deceleration of thevalve piston during acceleration. The mass compensa tor function of thespool increases the change in pressure required to effect movement ofthe piston valve.

Reference is now directed to FIG. 12 which is a diagram whichillustrates the time and pressure relationship between the lubricantpressure as sensed and as applied to the shaft. The diagram isapplicable to the embodiment shown in FIGS. 1 through 5 as well as theembodiments shown in FIGS. 6 through 9. PB represents the pressure atthe bottom of the shaft, while PT represents the pressure at the top ofthe shaft. C represents the sensed pressure change; whereas, Grepresents the pressure gained. in this regard, if the sensed pressurechange is negative, the gain is likewise negative. Tests have indicatedthat the gain may be many times the sensed pressure change and theamount of gain is determined by the overall size andrelative size of thevarious passages. The sensed pressure change will reach its peakslightly ahead of the peak gain in pressure, the difference beingindicated by RT in the diagram. I i

Reference is now directed to FIG. 14, which is a diagrammatical view ofthe shaft and confronting portion of the bearing. The eccentricity ofthe shaft and the spacing between the shaft and bearing is greatlyexaggerated for purposes of illustration. in FIG. 14, L represents theload on the shaft, PB represents the pressure at the bottom of theshaft, PT represents the pressure at the top of the shaft, and the spacebetween the shaft and bearing, designated LF represents the lubricantfilm. During operation, the effective top and bottom of the shaft, whichlie in a plane passing through the bearing center BC and shaft centerSC, are displaced downward.

The construction illustrated in FIG. 14 is directed particularly to theembodiment shown in FIGS. 6 through 9, but is also applicable to theembodiment shown in FIGS. 1 through 5. Whether the shaft rotates in asingle direction as indicated by R, or in both directions, the ports 66are located in the central region of the bearing cavities 64, andintersect an axially extending channel 105.

The portions of each cavity 64 extending in opposite directions fromeach channel 105 forms opposed pumping lands 64a and 64b; that is, therotation of the shaft tends to move the lubricant film with the shaft,creating a dynamic fluid pressure. The dynamic fluid pressure in thepumping land 64a extending in the direction of shaft rotation (clockwisein FIG. 14), the dynamic fluid pressure is positive; hence, produces asignal for increased fluid with increased shaft speed. The dynamic fluidpressure in the pumping land 64b extending in a direction opposite toshaft rotation is negative; hence, produces a signal for decreased fluidwith increased shaft speed. That is, the dynamic fluid pressures in thepumping lands 64a and 64b oppose each other. By shifting the location ofthe inlet channel 105, the effect of the dynamic fluid pressures may becancelled or made negative or positive depending on the conditions forwhich the fluid bearing is designed.

A further pumping effect is produced as a result of any convergence ordivergence of the shaft and bearing surfaces due to the eccentricity ofthe shaft. More particularly, a positive wedging pressure WP+ occurswhere the shaft and bearing surfaces converge, and a negative wedgingpressure WP- occurs where the shaft and bearing surfaces diverge. Theamount of convergence or divergence is, of course, small due to the factthat the thickness of the lubricant film is small, and thus the amountof eccentricity of the shaft is minimal.

Ideally, the center of gravity of the rotating mass should coincide withthe shaft center, but as a practical matter, this is difficult toattain. For purposes of illustration, the center of gravity, designatedCG, is shown as located to one side of the shaft center, creating acentrifical force through the center of gravity, indicated by CF, whichtends to produce a whirl or eccentric rotation of the shaft. This forceis resisted by the pressures existing at PT and PB and by the wedge liftforce.

Reference is now directed to FIG. 13 which shows diagrammatically therelationship between bearing film pressure and bearing film thickness,in which line A represents bearing film pressure with the sensing valveheld in a near closed position, line B represents the bearing filmpressure as increased when the sensing valve is full open, line Cindicates the supply pressure. The broken line D indicates the bearingfilm pressure as increased due to shaft rotation, this being the effectof pumping lands 106. E represents the bearing film pressure asincreased with increased flow through the sensing valve.

Reference is now directed to FIG. 11. This figure illustrates thepressure sensing control valve pressures P, through P and the directionof the fluid weight flow W, 1 with arrows. The mathematical model of thepressure sensing control valve is an outline of the calculationsrequired to show the control working. These calculations are outlined asfollows:

I. Set P min with the valve closed and with area A,. Then set F, max P,max with the resistance to flow through the flow passages and calculatethe following:

2. Flow W, and W, 4

. Pressure P P P,,, Area A and A; for P P,,.

. P P,,, Area A and A for P P Then set P min P, min and calculate theflow W,

10. Flow W 1 12. Pressure P 15. P P A and A for ,P P

16. Calculate area A,; with an area A, for the control to have nearinfinite gain and an incipient change in area A will open or close thevalve providing P ITM. 5 and ITM. l2.

1?. Calculate area A with an area A for the control to have proportionalgain and the amplification in pressure P will be proportional to a smallchange in area A, Set volume P greater than volume P, in the sensingcircuit for compressible fluids. Set A P (P ITM. 5 P ITM. 12).

Reference is now directed to FIG. 15. This figure illustrates the changein P pressure to pressure P in response to an incipient positive ornegative area A change. This figure also illustrates the fade out ofdifferential pressure created with the change in P between P, and P, asthe valve stroke changes and P, again equals P at another valve positionsuch as position 2 or 3. The calculations required to show this valveaction are as follows:

1. Calculate the valve spool inertia forces.

2. Calculate the differential pressure forces available to acceleratethe valve spool.

Near the open end of the valve spool stroke P,

increases as indicated with P," and near the closed end of the valvespool stroke P increases as indicated with P," to limit the valvestroke, preventing spool impact with the enclosing structure. This isaccomplished with the valve spool end jet flow as the valve spool movesnear the end of its stroke.

Referring back to the mathematical theory of fluid bearings and also toFIGS. 11 through 14, it has been demonstrated that:

l. The fluid flow control accomplished by the pressure sensing valveprovides for infinite gain or floating control action" over a wide inletand discharge range.

2. Increasing the feedback flow and reducing control vent flow from theinfinite gain condition, provides the control with lower gain that isproportional to a small change inthe discharge exit area. This isPROPORTIONAL CONTROL ACTION."

3. The controls frequency response is increased by:

A. Decreasing the reset flow.

B. Increasing the available differential pressure range for moving thevalve.

C. Decreasing the mass of the valve.

D. Increasing the ratio of the valve diameter to the valve stroke.

E. Reducing the required variation in flow through the valve whichreduces the valve stroke. For example, the required variation in flow isreduced by increasing the thin slot exit flow resistance in bearings.

4. Varying the control inlet pressure does not adversely affect thecontrol action.

5. Making the reset flow equal to the flow from the opposite end of thevalve to the same discharge, isolates the control from responding tochanges in the control discharge pressure, except for the feedbackcontrol action.

6. Modulating the control vent flow from one end of the valve providesthe control with remote pressure sensing capability.

7. Restricting or modulating the flow from the opposite valve end cavityprovides the control with override control capability.

8. Increasing the stiffness of the bearing film with the controlincreases the dashpot damping to resist excessive vibration buildup dueto slight rotor unbalance.

For example, the above equations point out that the centrifugal forcedue to the unbalance of a balanced rotor is greater than the fluid filmcan support at the natural frequency of vibration of the rotor on thesupporting fluid film. These equations also point out that the vibrationvelocity increases with frequency at a particular vibration amplitude.Therefore since dashpot damping increases with velocity, the naturalfrequency of vibration only has to be increased until dashpot dampingabsorbs the excitation energy due to the unbalance of the rotor toprevent vibration amplitude build up. Lower viscosity fluids have lowerviscous damping. Therefore, to use lower viscosity fluids and obtainlower viscous friction horsepower losses at high rotational frequencies,the stiffness of the fluid film is increased to increase vibrationvelocity and also to increase bearing load capacity. The dynamic liftwedge forces and the pumping land lift forces are small if the shaftdisplacement from the bearing center is small, but these forces combinewith the dashpot damping forces and the differential pressure forcescreated with the control to increase the bearing film stiffness. Aspointed out in FIGS. 12, 13 and 14.

Reference is now directed to FIGS. 16 through 31 which are directed tovarious embodiments of the pressure sensing control valve as adapted tothe operation and control of fluid devices other than bearings. Morespecifically, the embodiment shown in FIGS. 16 through is directed to afluid motor control wherein the motive fluid is maintained at apreselected pressure.

This embodiment includes a valve body 111, having a longitudinal bore112 in which is formed an annular inlet channel 113, outlet channel 114and vent channel 115. An integral internally screwthreaded inlet fitting116 extends from one side of the valve body 111 and communicates withthe inlet channel 113. Similarly, an integral internally screwthreadedoutlet fitting 117 extends from the opposite side of the valve body 111and communicates with the outlet channel 114. The vent 'channel 115communicates with a vent port 118. The

ting 123, which overlies the outer end of the bore 112. A spring 124 isinterposed between the fitting or cap 123 and the piston 122.

The opposite end of the bore 112 within the extension 120 receives amanually operated disk 125, provided with an axially extending stern126, which protrudes from the bore. The stem 126 extends through an endplug 127. An internally screwthreaded fitting 128 is received on theextension 120.

Mounted between the plugs 121 and 127 is a valve piston which may beidentical to the valve piston described in connection with FIGS. 6through 9 and to which the same reference characters are applied. Also,relating to the previous construction, a sensing chamber is formedbetween the piston 70 and the disk 12S and a damping chamber 81 isformed between the piston and the end plug 121.

The bypass control plug 121 is provided with a pair of diametricallydisposed sockets and 131, which are connected respectively with theinlet fitting 116 through a bypass inlet 132 and with the outlet fitting117 through a bypass outlet 133. The sockets 130 and 131 are joined toaxially extending constricted passages 134 and 135 respectively. Thepassage 134 intersects a conical valve seat 136 formed in the outer endof the plug 121, whereas, the passage 135 intersects the outer end ofthe plug at one side of the valve seat 136.

The plug 121 is provided with a circular channel 137 which is connectedby a constricted passage 138 to the damping chamber 81 and also througha cross passage 139 to the socket 131. A screw valve 140 having atapered inner end intersecting the cross passage permits adjustment ofthe flow through the cross passage.

The channel 137 is provided with a radial passage 141, intersecting acentral socket 142 of small diameter centered in the conical valve seat136. The piston 122 is provided with a central valve tip 143 whichengages the valve seat 136. The piston 122 is provided with a centralstem 144, having a central passage 145 constricted at its inner end toform a valve seat. Outwardly therefrom the passage 145 is intersected bya side passage 146. The passage 145 is internally screwthreaded toreceive a needle valve 147. The needle valve controls the venting offluid through the passage, 145 and side passage 146. The piston 122 maybe sealed in the bore 112 by a labyrinth seal channel 148.

At its juncture with the stem 126, the disk 125 is provided with a valveseat 149 and the opposing portion of a the end plug 127 is provided witha valve face 150. A constructed port 151 extends alongside the stem 126within the valve seat 149 so as to be closed when the disk 125 is seatedagainst the end plug 127. In addition, radially outward from the valveseat 149, the disk 125 is provided with one or more equalizer ports 152.Also, the end plug 127 is provided with a vent passage 153.

The screwthreaded fittings 123 and 128, the screw valve 140 and theneedle-valve 147 are provided with conventional friction plugs 154 whichserve to assure that these members will not change their adjustmentduring operation of the valve.

Operation of the valve illustrated in FIGS. 16 through 25 is as follows:

The valve piston operates in the same manner as the valve pistondescribed in connection with FIGS. 6 through 9. More particularly, if aslight change in pressure occurs at the outlet fitting 117, thispressure change is communicated to the sensing chamber 80,

causing the valve piston to open, permitting transient peak flow to theoutlet and to whatever device connected therewith. This peak flow ismomentary for the pressure soon equalizes in the damping chamber 81,partially reducing the flow until it is in proportion to the demand. Byway of example, if the sensing valve is connected to a hydraulic orpneumatic motor, increased torque on the motor will cause a rise inpressure in the outlet fitting 117, causing the valve to open and supplymore fluid to maintain the motor in operation.

In some applications, it is desirable that the pressure supplied to thetool not exceed a predetermined value. For instance, if the fluid motoroperates a torque wrench, it may be desirable to limit the torque to apredetermined value. This may be accomplisned by adjusting the fitting123 which may be considered as a torque control. By adjustment of thetorque control, a predetermined pressure at the outlet fitting 117 willopen the valve tip 143 so that fluid is now admitted from the inletfitting 116 through the passage 134. As a result, pressure is appliedthrough the radial passage 141 and passage 138 to the damping chamber81, forcing the valve piston 70 toward its closed position. The rate atwhich the valve piston closes is dependent upon the rate at which fluidis vented through ports 152 and passage 153. As a consequence, thetorque motor is relaxed momentarily so that the tool may be removed fromthe bolt or other device to which the torque was applied. The sensingvalve formed by the lips 73 and 741 does not completely close so thatwhen the torquing tool is applied to another device, the resistance torotation builds up a back pressure which causes the valve piston toopen, supplying motive fluid in accordance with the back pressuresupplied to the sensing chamber 80.

As has been pointed out previously, it is not intended that the valvelips 73 and 74 form a complete seal. The minimum distance between thevalve lips determines the minimum flow through the sensing valve. Thisminimum flow may be adjusted by adjustment of the fitting 128.

The disk 125 and its stem 126 provides a manual means to overcome thecontrol afforded by the valve; that is, by pressing inward on theexposed end of the stem 126, the valve can be manually forced to itsfull open position so that full motive fluid pressure may be applied tothe tool or other device connected therewith. The relative size of theport or ports 151, equalizer ports 152 and vent passage 153 are suchthat once the disk 125 is unseated from the valve seat 149 there is apressure built up behind the disk which supplements the pressure appliedmanually. However, once the stem 126 is released, the valve port formedby the valve seat 149 and valve face 150 closes.

Reference is now directed to FIGS. 26, 27 and 28. This embodiment of thepressure sensing control valve is adapted for use as a highly sensitiveand accurate pressure regulator, intended primarily for use with air ora gas, but not limited thereto. Most of the parts, including the valvepiston 70, are retained and are given similar reference characters.However, the needle valve 147, adjustment valve 140 and associatedpassages are omitted as well as bypasses 132 and 133. The functions ofchannels 113 and 115 are reversed, as well as the sensing chamber 80 anddamping chamber 81. In place of the relatively large vent port 118, arestricted vent port 155 is provided. The opposing passages 82 and 83are similar in size and both function to effect a damping or stabilizingaction of the valve piston 70.

Operation of the pressure sensing control valve, as adapted for use as apressure regulating valve, is as follows: chamber When the pressuredownstream from the outlet fitting 117 increases, a backflow occurs inpassages 133, 113 and to increase pressure against the piston 122,causing the valve 143 to open. The pressure in the chamber 80 isnormally equal to pressure at the inlet fitting 116, by reason of theconnection through passage 77, chamber 76 and passages 78 and 84, andthus is higher than the pressure at the fitting 117. Consequently, flowoccurs momentarily from the chamber80 through passages 138, channel 137and passages 141 and 142. This causes the valve piston 70 to move towardits closed position, reducing flow from the inlet 116 to the outlet 117.

When the pressure downstream from the fitting 117 decreases, the piston122 causes the valve 143 to close, permitting pressure to build up inchamber 80, which causes the valve piston 70 to move toward it openposition.

When used as a regulator valve, the adjustment afforded by the screw cap128 is usually not needed, unless a maximum flow adjustment is desired.

Reference is now directed to FIGS. 29, 30 and 31. This embodiment of thepressure sensing control valve is adapted for use as a fluid motorcontrol in cases wherein it is desired to reuse the liquid; for example,in a closed system whether the fluid be a gas or a liquid. Also, thisembodiment is intended to be responsive to an extraneous sensing devicesuch as a device responsive to temperature, pressure, accelerationforces or other forces. The pressure sensing control valve beingresponsive to a signal from the sensing device to effect control of afuel or other motive fluid, while utilizing only a small amount of thetotal fluid in the system.

This embodiment is closely related to the construction shown in FIGS.16, 17 and 18 and most of the reference characters used in the precedingembodiment apply. The essential changes are those which permit a closedsystem; more specifically, the body 111 is modified to provide a returnflow fitting 156 connected to the vent channel 15 in place of anexhaust. The fitting 156 is connected by a passage 157 to the regionbetween the body 111 and the cap 123. The cap is modified to provide aclosed end so as to form a closed pressure chamber 158 and the cap skirtis provided with a seal ring 159. A sensing port fitting 160 is added 40the valve body 111, and is connected by a passage 161 to the circularchannel 137.

The end plug 12 is provided with a seal ring 162 and the stem 126 isprovided with a seal ring 163. Also the end plug 127 is provided with anannular channel 164 connected by a passage 165, formed in the valve bozy111, with the channel 115. Also, a passage 166 connects the channel 164with the chamber formed between the end plug 127 and the disk 125.

Operation of the embodiment shown in FIGS. 29, 30 and 31 is essentiallythe same as the embodiment shown in FIGS. 16, 17 and 18, except that itis installed in a closed system. Port 156 is connected to a tank orreservoir, not shown. Port 160 is connected to a sensing device, notshown, which, in turn, is connected to the tank or reservoir. Pressurechanges at port 160 causes the valve piston 70 to respond by appropriateincrease or decrease in flow to the motor or other apparatus connectedwith the valve.

Reference is now directed to FIG. 32 which illustrates a modified pistonvalve 167 which may be substituted for the valve piston 70 in any of thepreceding embodiments of the pressure sensing control valve. Forpurposes of illustration, the modified piston valve is shown in relationto the embodiment illustrated In FIGS. 16 through 18.

The modified piston valve 167 is provided with a conical bore 168 closedat its smaller end and diverging toward the damping chamber 81. Receivedin the bore 168 is a cone 169, having a longitudinal passage 170. Thevalve piston I67, like the valve piston 70, is provided with an externalannular channel 72, a set of sensing chamber passages 82 and dampingchamber passages 83 communicating respectively with the sensing chamber80 and damping chamber 81. Also, sets of passages 77, 78 and 79 extendradially from the conical bore 168. The passages 79 are intersected byaxial passages 84, communicating with the sensing chamber 80.

The surrounding parts of the pressure sensing control valve are the sameas in FIGS. l6, l7 and 18, except that a passage 17] continues from thesocket 142 to the damping chamber 81.

The conical space between the cone I69 and the confronting walls of thevalve piston 167 forms a chamber which supplements or superccdes thefunction of the damping chamber 81. That is, fluid into and out of theconical chamber, as the valve piston 167 moves to increase or decreasefluid flow, produces a damping action. Normally the cone 169 does notmove away from the annular rib 84a; instead, it is held fixed by fluidpressure, except it tends to center itself within the valve piston 167just as the piston tends to center itself in the bore 75. As is the casewith the valve piston 70, the fluid forces acting on the valve piston167 function in a manner analogous to a spring.

It should be noted that the embodiments shown in FIGS. 16 through 32, aswell as the previous embodimcnts, the pressure fluid passing through themain passageways from the inlet to the outlet exerts equal force inopposite directions on the valve piston 70 or 167 so that this, the mainportion of the fluid, does not cause any movement of the valve piston;thus, the valve piston tends to remain in fixed position unless changein pressurein the sensing or damping chamber occurs. Only the very smallvolume of the pressure fluid present in the sensing chamber 80 ordamping chamber 81 is effective in moving the valve piston, and thetotal movement of the valve piston is quite small. Also, the forcesrequired to effect movement of the valve piston is low because the valvepiston is fluid supported. Still further, the passages communicatingwith the sensing and damping chambers are quite small and may be of suchsize that the fluid moves by capillary action. The passages which ventfluid from the sensing and damping chambers are smaller than thepassages supplying fluid thereto to permit the buildup or drop inpressure necessary to move the valve piston.

I claim:

1. A fluid, lubricated bearing, comprising:

a. a bearing body including a bearing wall confronting a rotatableshaft, said bearing wall having a set of fluid receiving bearingcavities, and said bearing body also including a corresponding set offluid re ceiving pressure sensing cavities;

b. said bearing body also having a set of valve bores corresponding tosaid bearing and sensing cavities, pressurized lubricant fluid supplypassages communicating individually with said valve bores, and fluidexchange passages communicating between each valve bore and acorresponding bearing cavity and sensing cavity;

c. a valve reciprocable in each valve bore between an open position forsupplying fluid to the corresponding bearing cavity, and a closedposition minimiz ing the supply of fluid thereto;

d. each of said valves defining with said bearing body a pressurechamber and, upon predetermined decrease in pressure therein, movabletoward its closed position and, upon predetermined increase in pressuretherein, movable toward its open position,

e. said pressure chamber being continuously exposed to said fluidsupply, and continuously in communication with a corresponding sensingcavity;

f. and means restricting supply of fluid to said pressure chamberwhereby the pressure in said pressure chamber varies with pressure insaid sensing cavity to cause said valve to open when pressure in saidsensing cavity increases, and to close, when pressure in said sensingchamber decreases.

A bearing, as defined in claim 1,- wherein:

a portion of said fluid is directed between each valve and its bore tosuspend said valve therein.

A bearing, as defined in claim I, wherein:

a. the bearing is adapted to be supplied with a gas- A bearing, asdefined in claim 1, wherein:

a. the bearing is adapted to be supplied with a liquid fluid.

5. A fluid lubricated bearing, comprising:

a bearing body including a bearing wall confronting a rotatable shaft,said bearing wall having a set of fluid receiving bearing cavities, andsaid bearing body also including a corresponding set of fluid receivingpressure sensing cavities; Y b. valve means for supplying a pressurizedlubricant fluid to each of said bearing cavities and its correspondingsensing cavity, said valve means movable in response to an increase inpressure in the corresponding sensing cavity to increase the supply offluid to its related bearing cavity, and movable in response to decreasein pressure in said sensing cavity to decrease the supply of fluid tosaid bearing cavity.

6. A bearing, as defined in claim 5, wherein:

a. said sensing cavities also confront the shaft and a bleed cavityconfronting the shaft separates each sensing cavity from itscorresponding bearing cavity.

'7. A hearing, as defined in claim 5, wherein:

a. said cavities are incorporated in said valve means.

8. The combination with a source of lubricant fluid under pressure, afluid lubricated bearing and a shaft defining with the bearing a set ofpressure fluid receiving cavities, the walls of each cavity forming apressure fluid operating means, of a pressure sensing valve for eachpressure fluid operating means, comprising:

a. a valve body structure having a valve cavity intersected by an inletport connected with the pressure fluid source and an outlet portconnected with the pressure fluid operated means;

b. a pressure sensing means in the cavity defining a passageway betweenthe inlet port and outlet port,

pressure sensing means in a direction to decrease flow of fluid to theoperated means;

e. means forming a restricted passageway between the outlet port and thepressure sensing chamber and movable to regulate the supply of pressurefor effecting movement of the pressure sensing fluid from the inlet portthrough the outlet port means; thereby to control the pressure fluidoperated f. and means for damping the movement of the pres means, saidpassageway having opposed walls of sure sensing means. equal areawhereby the pressure sensing means is 10. The combination as defined inclaim 9, wherein: insensitive to pressure in said passageway; a. thebearing body also includes a set of pressure c. the cavity and pressuresensing means having consensing recesses axially spaced from the bearingrefronting walls forming an expansible and contractcesses andcommunicating with the damping ible pressure sensing chamber to effect,upon inmeans, crease of pressure therein, movement of the pres- 11. Thecombination, as defined in claim 9, wherein: sure sensing means in adirection to increase flow a. each cavity is cylindrical and includesend walls; of fluid to the operated means, and to effect, upon b. thepressure sensing means is a piston reciprocable decrease of pressuretherein, movement of the between the end walls; pressure sensing meansin a direction to decrease 0. one end wall of each cavity and theconfronting flow of fluid to the operated means; end of the piston formsthe pressure sensing chamd. means forming a restricted passagewaybetween her;

the outlet port and the pressure sensing chamber (1. and the other endwall of each cavity confronting for effecting movement of the pressuresensing the other end of the piston defines a second presmeans; suresensing chamber which forms said damping e. and means for damping themovement of the presmeans.

sure sensing means. 12. A pressure sensing lubricant control means for9. Thc combination with a source of lubricant presbearings, comprising:sure fluid, and a pressure fluid operated means in which a. a bearingbody structure for journalling a shaft, ina pressure fluid is circulatedtherethrough, of a preseluding a set of circumferentially spaced bearingsure sensing valve, comprising: fluid recesses confronting the shaft, acorresponda. a rotatable element; ing set of valve bores, each borehaving an inlet, an b. a bearing body structure confronting therotatable outlet and a connection between each recess and element andhaving a set of cavities, each interthe outlet; sected by an inlet portconnected with the pressure b. a valve piston movable in each bore andhaving fluid source and an outlet port connected with the fluid flowpassages communicating between the pressure fluid operated means;corresponding inlet and outlet, the flow passages c. a pressure sensingmeans in each cavity defining a having effectively equal and oppositepressure surpassageway between the inlet port and outlet port, faceswhereby the pressure of fluid flowing therein and movable to regulatethe supply of pressure has essentially no effect on movement of thevalve fluid from the inlet port through the outlet port piston; therebyto control the pressure fluid operated c. each valve piston andcorresponding opposing means, said passageway having opposed walls ofwalls defining opposed sensing and damping chamequal area whereby thepressure sensing means is bers to effect movement of the valve piston;insensitive to pressure in said passageway; d. and pressure sensingcontrol means for each bore d. each cavity and its pressure sensingmeans having and its piston including restricted passagescommuconfronting walls forming an expansible and connicating betweenboth the chambers and the outlet tractible pressure sensing chamber toeffect, upon operable to effect increase in the fluid passing increaseof pressure therein, movement of the presthrough the flow passages withincreased pressure sure sensing means in a direction to increase flow atthe outlet and decreased flow therethrough with of fluid to the operatedmeans, and to effect, upon decreased pressure at the outlet. decrease ofpressure therein, movement of the

1. A fluid lubricated bearing, comprising: a. a bearing body including abearing wall confronting a rotatable shaft, said bearing wall having aset of fluid receiving bearing cavities, and said bearing body alsoincluding a corresponding set of fluid receiving pressure sensingcavities; b. said bearing body also having a set of valve borescorresponding to said bearing and sensing cavities, pressurizedlubricant fluid supply passages communicating individually with saidvalve bores, and fluid exchange passages communicating between eachvalve bore and a corresponding bearing cavity and sensing cavity; c. avalve reciprocable in each valve bore between an open position forsupplying fluid to the corresponding bearing cavity, and a closedposition minimizing the supply of fluid thereto; d. each of said valvesdefining with said bearing body a pressure chamber and, uponpredetermined decrease in pressure therein, movable toward its closedposition and, upon predetermined increase in pressure therein, movabletoward its open position, e. said pressure chamber being continuouslyexposed to said fluid supply, and continuously in communication with acorresponding sensing cavity; f. and means restricting supply of fluidto said pressure chamber whereby the pressure in said pressure chambervaries with pressure in said sensing cavity to cause said valve to openwhen pressure in said sensing cavity increases, and to close, whenpressure in said sensing chamber decreases.
 2. A bearing, as defined inclaim 1, wherein: a. a portion of said fluid is directed between eachvalve and its bore to suspend said valve therein.
 3. A bearing, asdefined in claim 1, wherein: a. the bearing is adapted to be suppliedwith a gaseous fluid.
 4. A bearing, as defined in claim 1, wherein: a.the bearing is adapted to be supplied with a liquid fluid.
 5. A fluidlubricated bearing, comprising: a. a bearing body including a bearingwall confronting a rotatable shaft, said bearing wall having a set offluid receiving bearing cavities, and said bearing body also including acorresponding set of fluid receiving pressure sensing cavities; b. valvemeans for supplying a pressurized lubricant fluid to each of saidbearing cavities and its corresponding sensing cavity, said valve meansmovable in response to an increase in pressure in the correspondingsensing cavity to increase the supply of fluid to its related bearingcavity, and movable in response to decrease in pressure in said sensingcavity to decrease the supply of fluid to said bearing cavity.
 6. Abearing, as defined in claim 5, wherein: a. said sensing cavities alsoconfront the shaft and a bleed cavity confronting the shaft separateseach sensing cavity from its corresponding bearing cavity.
 7. A bearing,as defined in claim 5, wherein: a. said cavities are incorporated insaid valve means.
 8. The combination with a source of lubricant fluidunder pressure, a fluid lubricated bearing and a shaft defining with thebearing a set of pressure fluid receiving cavities, the walls of eachcavity forming a pressure fluid operating means, of a pressure sensingvalve for each pressure fluid operating means, comprising: a. a valvebody structure having a valve cavity intersected by an inlet portconnected with the pressure fluid source and an outlet port connectedwith the pressure fluid operated means; b. a pressure sensing means inthe cavity defining a passageway between the inlet port and outlet port,and movable to regulate the supply of pressure fluid from the inlet portthrough the outlet port thereby to control the pressure fluid operatedmeans, said passageway having opposed walls of equal area whereby thepressure sensing means is insensitive to pressure in said passageway; c.the cavity and pressure sensing means having confronting walls formingan expansible and contractible pressure sensing chamber to effect, uponincrease of pressure therein, movement of the pressure sensing means ina direction to increase flow of fluid to the operated means, and toeffect, upon decrease of pressure therein, movement of the pressuresensing means in a direction to decrease flow of fluid to the operatedmeans; d. means forming a restricted passageway between the outlet portand the pressure sensing chamber for effecting movement of the pressuresensing means; e. and means for damping the movement of the pressuresensing means.
 9. The combination with a source of lubricant pressurefluid, and a pressure fluid operated means in which a pressure fluid iscirculated therethrough, of a pressure sensing valve, comprising: a. arotatable element; b. a bearing body structure confronting the rotatableelement and having a set of cavities, each intersected by an inlet portconnected with the pressure fluid source and an outlet port connectedwith the pressure fluid operated means; c. a pressure sensing means ineach cavity defining a passageway between the inlet port and outletport, and movable to regulate the supply of pressure fluid from theinlet port through the outlet port thereby to control the pressure fluidoperated means, said passageway having opposed walls of equal areawhereby the pressure sensing means is insensitive to pressure in saidpassageway; d. each cavity and its pressure sensing means havingconfronting walls forming an expansible and contractible pressuresensing chamber to effect, upon increase of pressure therein, movementof the pressure sensing means in a direction to increase flow of fluidto the operated means, and to effect, upon decrease of pressure therein,movement of the pressure sensing means in a direction to decrease flowof fluid to the operated means; e. means forming a restricted passagewaybetween the outlet port and the pressure sensing chamber for effectingmovement of the pressure sensing means; f. and means for damping themovement of the pressure sensing means.
 10. The combination as definedin claim 9, wherein: a. the bearing body also includes a set of pressuresensing recesses axially spaced from the bearing recesses andcommunicating with the damping means.
 11. The combination, as defined inclaim 9, wherein: a. each cavity is cylindrical and includes end walls;b. the pressure sensing means is a piston reciprocable between the endwalls; c. one end wall of each cavity and the confronting end of thepiston forms the pressure sensing chamber; d. and the other end wall ofeach cavity confronting the other end of the piston defines a secondpressure sensing chamber which forms said damPing means.
 12. A pressuresensing lubricant control means for bearings, comprising: a. a bearingbody structure for journalling a shaft, including a set ofcircumferentially spaced bearing fluid recesses confronting the shaft, acorresponding set of valve bores, each bore having an inlet, an outletand a connection between each recess and the outlet; b. a valve pistonmovable in each bore and having fluid flow passages communicatingbetween the corresponding inlet and outlet, the flow passages havingeffectively equal and opposite pressure surfaces whereby the pressure offluid flowing therein has essentially no effect on movement of the valvepiston; c. each valve piston and corresponding opposing walls definingopposed sensing and damping chambers to effect movement of the valvepiston; d. and pressure sensing control means for each bore and itspiston including restricted passages communicating between both thechambers and the outlet operable to effect increase in the fluid passingthrough the flow passages with increased pressure at the outlet anddecreased flow therethrough with decreased pressure at the outlet.